The circuit described here is of an economical smooth variable power supply which offers 0V to 24V. It provides all controls and short circuit protection with acceptable regulation and a ripple free supply and yet uses very few components.

The transformer used is a readily available 12V-0-12V, 2A type connected at the end terminals for 24V, 1A output. After rectification and filtering, a constant reference voltage is obtained by the 24V, 500mW zener diode.

The pots used for voltage variation are 23mm carbon-film linear type and for current limit 10 ohm, 1w wirewound type is used. All the components can be connected on a group board. Necessary heatsinks should be provided for both SL100 and 2N3055.

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